Antennas for wireless voice and/or data communications typically include an array of radiating elements connected by one or more feed networks. For efficient transmission and reception of Radio Frequency (RF) signals, the dimensions of radiating elements are typically matched to the wavelength of the intended band of operation. Because the wavelength of the GSM 900 band (e.g., 880-960 MHz) is longer than the wavelength of the GSM 1800 band (e.g., 1710-1880 MHz), the radiating elements for one band are typically not used for the other band. Radiating elements may also be dimensioned for operation over wider bands, e.g., a low band of 698-960 MHz and a high band of 1710-2700 MHz. In this regard, dual band antennas have been developed which include different radiating elements for each of the two bands. See, for example, U.S. Pat. No. 6,295,028, U.S. Pat. No. 6,333,720, U.S. Pat. No. 7,238,101 and U.S. Pat. No. 7,405,710, the disclosures of which are incorporated by reference.
Additionally, base station antennas (BSA) with +/−45 degree slant polarizations are widely used for wireless communications. Two polarizations are used to overcome of multipath fading by polarization diversity reception. The vast majority of BSA have +/−45 degree slant polarizations. Examples of prior art can be crossed dipole antenna element U.S. Pat. No. 7,053,852, or dipole square (“box dipole”), U.S. Pat. No. 6,339,407 or U.S. Pat. No. 6,313,809, having 4 to 8 dipole arms. Each of these patents are incorporated by reference. The +/−45 degree slant polarization is often desirable on multiband antennas.
There are numerous ways to fabricate cross polarized radiating elements. See, for example, U.S. Pat. No. 7,688,271, the disclosure of which is incorporated by reference. In this example, the printed circuit boards (“crossed legs”) have a dipole radiating element attached at the top, and are soldered into a feed network at the bottom. This is accomplished by including a pair of tabs on the legs, which pass through corresponding slots on a base PCB.
While low cost, a disadvantage of such an assembly is that the solder joints provide both an electrical connection and a mechanical connection. Mechanical stresses on the legs may cause a premature failure of the solder joints and loss of signal connectivity.